How to use the is-lite.function function in is-lite

callback = data => {
    const { callback } = this.props;

    /* istanbul ignore else */
    if (is.function(callback)) {
      callback(data);
    }
  };

const hasReactElement = isValidElement(left) || isValidElement(right);
  const hasUndefined = is.undefined(left) || is.undefined(right);

  if (getObjectType(left) !== getObjectType(right) || hasReactElement || hasUndefined) {
    return false;
  }

  if (is.domElement(left)) {
    return left.isSameNode(right);
  }

  if (is.number(left)) {
    return left === right;
  }

  if (is.function(left)) {
    return left.toString() === right.toString();
  }

  for (const key in left) {
    /* istanbul ignore else */
    if (hasOwnProperty(left, key)) {
      if (typeof left[key] === 'undefined' || typeof right[key] === 'undefined') {
        return false;
      }

      type = getObjectType(left[key]);

      if (['object', 'array'].includes(type) && isEqual(left[key], right[key])) {
        continue;
      }